Tunnel construction



Sept; 20, P. ZUCCO TUNNEL CONSTRUCTI 0N Original Filed Aug. 20, 1923 INVEN TOR. PIERRE ZUC'CO.

BY 49 m Md I 2 AT TORNE Y5- Patented Sept. 20, 1927.

UNITED STATES PATENT OFFICE.

TUNNEL CONSTRUCTION.

Application filed August 20, 1923, Serial No. 658,236. Renewed March 19,19 27.

This invention relates to tunnel construction, and has for its object tosimplify and improve the construction of concrete tunnels.

This object I accomplish by making use of precast forms which are lightin weight, and therefore readily handled such forms being provided withmeans for assembling them into the shape of a tunnel, and thereafterapplying a back fill of coarser concrete to take care of the stressesand Weightsur rounding the tunnel.

One form which my invention may assume is exemplified in the followingdescription and illustrated in the accompanying drawing, in which Fig. 1shows a vertical sectional view of a tunnel constructed in accordancewith my invention.

Fig. 2 shows a plan View, partly in section, of the same.

The tunnel has its sides and top all formed of curved concrete slabs orsections 10 and 11 which are pro-cast and make comparatively thin and ofa length such as to permit handling without special appliances. Thesecurved sections meet at their upper ends to form an arch and at theirlower ends they rest on a floor or invert 12 which may be pre-cast inslabs or sections or poured in place, as desired. Each section 10 and 11is formed with a groove 13 at one of its'curved edges so that adjacentsections may be bonded together by a filling of cement within thegroove. 1

It may also be desirable to employ reinforcing rods, as indicated at 14,in each of the sections, such rods, in the case of the sections, 10 and11, extending vertically of the slab and projecting from its upper edgeso as to enter a core in the opposite section, as shown in Fig. 2. It ispreferable to arrange the sections so that the joints at opposite sidesof the center line will be staggeredt When the slabs or sections are inplace a concrete back filling is applied. This consists of a leanconcrete or mortar which may be poured or shot into place. Such backfilling may contain reinforcements 16 here enough to be handled andsupport the bacf additional strength is required. The sections 10 and-11may be made extremely thin, as it is only necessary that they be madestron filling while the latter is being poured.

Vhere a tunnel of the character is used for carrying or conducting wateronly the precast sections need bennadeof a rich or compact mixture, suchas will exclude water. The back filling in such cases may be made of alean and porous mixture, thus effecting a saving in the construction ofthe tunnel.

The present tunnel construction permits the use of sections which may becomparatively thin and light, since they are only required to supportthe weight of the back fill when serving to furnish the main support ofthe tunnel. The staggered arrangement of the sections is also a matterof some importance;

Various changes in the construction and arrangement of the several partsherein shown and described may be employed without departing from thespirit of my inven tion as disclosed in the appended claims.

Having nowparticularly described my invention, what I claim and desireto secure by Letters Patent is:

1. A tunnel structure comprising in any cross-section a bottom memberand side members, the latter meeting at the top of the roof and definingsaid roof, all of said members being thin, are-cast units, and servingas a lining for the tunnel, and a filling of concrete covering the outerperiphery of said members and occupying the space between such membersand the Walls of the tunnel excavation.

2. A tunnel structure comprising in any cross-section a floor, side androof members, the side and roof members being thin, precast units ofcemetitious material, serving as a lining for the tunnel and a supportfor the back filling, and a filling of concrete covering the outerperiphery of said members and occupying the space between such membersand the walls of the tunnel excavation.

PIERRE ZUCCO.

